Edward Arthur, a nuclear physicist at Los Alamos National Laboratory in New Mexico, stands by an accelerator used in a process that sends neutrons smashing into plutonium atoms. The experimental procedure attempts to hasten radioactive decaynormally 240,000 years for plutonium 239by breaking atoms into parts that decay faster. If proved, the technique could reduce the time necessary to contain spent nuclear reactor fuel in an underground repository, rendering this highly radioactive waste essentially harmless in a few hundred years.